PURPOSE: 1. To evaluate the efficacy of selected antiviral drugs in the prevention and treatment of ophthalmitis in the newborn rat due to herpes simplex type 2 (HSV-2). 2. to monitor the effects of these antiviral drugs on ocular development in the treated neonatal rat. Wistar rats will be inoculated intracerebrally at 5 days of age with HSV-2. Beginning at 24 hours post inoculation (pi), animals will be treated with: 1. The purine analogue adenine arabinoside (ara-A); 2. Ara-A and pentostatin (an adenosine deaminase inhibitor); 3. Levamisole, an immunopotentiating substance; or 4. Isotonic saline, thus serving as inoculated, control animals. The efficacy of treatments will be evaluated using criteria such as; 1. survival rates, 2. incidence of ocular and brain lesions as observed by light and electron microscopy, 3. titers of HSV-2 in the eyes of treated and control animals, 4. drug-related lesions (if any) present in the eyes of treated animals. PURPOSE: PART II - 1. To study the retinal lesions in newborn rats inoculated with HNT strain of measles virus. Newborn rats will be inoculated intracerebrally with the HNT strain of measles virus (originally developed from the Philadelphia 26 strain by Burnstein et al, 1964). Eyes will subsequently be processed for light and electron microscopy, and viral isolation studies.